Make volume curve cubed instead of squared

src/scheme.rs

@@ -39,16 +39,17 @@ impl AudioScheme {
     pub fn buffer(&mut self) -> [(i16, i16); HW_BUFFER_SIZE] {
         let mut mix_buffer = [(0i16, 0i16); HW_BUFFER_SIZE];
 
+        // Multiply each sample by the cube of volume divided by 100
+        // This mimics natural perception of loudness
+        let volume_factor = ((self.volume as f32) / 100.0).powi(3);
         for (_id, handle) in self.handles.iter_mut() {
             match handle {
                 Handle::Audio { flags: _, ref mut buffer } => {
                     let mut i = 0;
                     while i < mix_buffer.len() {
                         if let Some(sample) = buffer.pop_front() {
-                            // Multiply each sample by volume squared divided by 100 squared
-                            // This feels better than just multiplying by volume divided by 100
-                            let left = ((sample.0 as i32 * self.volume * self.volume) / 10000) as i16;
-                            let right = ((sample.1 as i32 * self.volume * self.volume) / 10000) as i16;
+                            let left = (sample.0 as f32 * volume_factor) as i16;
+                            let right = (sample.1 as f32 * volume_factor) as i16;
                             mix_buffer[i].0 = mix_buffer[i].0.saturating_add(left);
                             mix_buffer[i].1 = mix_buffer[i].1.saturating_add(right);
                         } else {